Conservation wildflower plantings do not enhance on-farm abundance of Amblyomma americanum (Ixodida: Ixodidae)

Authors: MCCULLOUGH, CHRISTOPHER - Virginia Tech; Angelella, Gina; O'ROURKE, MEGAN - National Institute Of Food And Agriculture (NIFA)

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2020
Publication Date: 9/9/2020
Citation: Mccullough, C.T., Angelella, G.M., O'Rourke, M.E. 2020. Conservation wildflower plantings do not enhance on-farm abundance of Amblyomma americanum (Ixodida: Ixodidae). Insects. https://doi.org/10.3390/insects11090617.
DOI: https://doi.org/10.3390/insects11090617

Interpretive Summary: Wildflower meadow plantings are a popular practice to help conserve pollinators on farms. However, it is unknown whether ticks use wildflower plantings as well, inadvertently allowing populations of these medically important pests to increase on farms. Scientists from Virginia Tech, one of whom is currently a researcher at USDA-ARS Wapato in Washington, investigated the abundance of ticks in wildflower plantings relative to weedy field margins and forested areas on farms in eastern Virginia and Maryland in 2018 and 2019. Tick surveys targeted the Lonestar tick, Amblyomma americanum (L.), because it is the most common species in the area and can transmit several diseases to humans. While sampling, we also measured temperature, humidity, vegetation height, and duff layer depth to compare with tick abundance across sampling locations. The abundance of Lonestar ticks in wildflower plantings did not differ from their abundance in weedy field margins on farms, and the most Lonestar ticks were collected from forested areas. Vegetation height was associated with tick abundance but differed by sample site and whether ticks were nymphs and adults. The association between vegetation height and tick abundance might be related to the behavior of white-tailed deer, an important Lonestar tick host. Overall, this research indicates wildflower plantings do not increase the risk of exposure to Lonestar ticks on farms

Technical Abstract: Planting wildflowers is a commonly suggested measure to conserve pollinators. While beneficial for pollinators, plots of wildflowers may be inadvertently performing an ecosystem disservice by providing suitable habitat for arthropod disease vectors like ticks. The lone star tick, Amblyomma americanum (L)., is a medically important tick species that might be able to utilize wildflower plantings as suitable habitat. In this two-year study, ticks were sampled using dry-ice baited traps from wildflower plots, weedy field margins, and forested areas to determine if wildflower plantings were increasing the on-farm abundance of A. americanum. Abiotic and biotic environmental variables were also measured to better understand which factors affect A. americanum abundance. We found no more A. americanum in wildflower plots than in weedy field margins. Forested areas harbored the greatest number of A. americanum sampled. The height of vegetation in the sampled habitats was a significant factor in determining A. americanum abundance. Depending on the sampled habitat and life stage, this relationship can be positive or negative. The relationship to vegetation height may be related to the behavior of the white-tailed deer and the questing success of A. americanum. Overall, wildflower plots do not pose an increased risk of exposure to A. americanum on farms